Method for coating a rubber wiper blade

ABSTRACT

In the process for coating the elastomeric rubber wiper a vaporous coating material is generated and activated by a plasma and/or laser; a protective coating is formed on a rubber wiper surface by exposing it to the vaporous coating material by CVD and/or PVD methods and process parameters for the coating process are controlled so that the protective coating includes at least three coating layers and has a total thickness of from 200 nm to 2 μm. The coating layers include at least one thicker softer elastic coating layer with elastomeric properties similar to those of the rubber wiper and other thinner harder coating layers having wear-resistant properties. The other thinner harder coating layers have respective hardness increasing from an inner most one to an outermost one of the other thinner harder coating layers.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention related to a coating process for a rubber wiperand, more particularly, to a coating process for a rubber wiper made ofelastomer material, in which a wear-resistant protective coating isformed on the rubber wiper by a chemical and/or physical vapordeposition method from a vaporous coating material generated andactivated thermally, by plasma and/or by laser.

2. Prior Art

Known windshield wipers possess a wiper arm incorporating a fasteningdevice secured to a drive shaft, a hinged portion connected therewith byway of a toggle joint, and a wiper rod rigidly secured to the hingedstructure. In addition, the windshield wiper possesses a wiper blade,featuring a bearing yoke assembly and a rubber wiper supported by it.The wiper blade is hinged on the wiper arm, whereby a hook-shapedextremity of the wiper rod projects between the two side cheeks of thebearing yoke, embracing a hinged bolt. The articulation constructed inthis fashion guides the wiper blade with its rubber wiper over thewindshield of the motor vehicle, whereby the hinged portion and thebearing yoke make it possible for the rubber wiper to adapt to thecurvature of the windshield. The requisite contact pressure of therubber wiper upon the windshield of the vehicle is achieved by at leastone tension spring, which braces the fastening device and the hingedstructure together with the wiper rod by way of the toggle joint.

The rubber wiper consists of an elastomer, for example a natural orsynthetic rubber. It has a head cleat connected via a rocker flange witha wiper lip butting against the windshield to be wiped. By way of therocker flange, the wiper lip is able to shift in inverse direction atthe turnabout point of its wiper travel, so as to retain at all times aproper angle to the windshield. When the wiper is activated, the rubberwiper glides over the windshield of the vehicle with its wiper lip,whereby the friction between the lip and the windshield causes theformer to abrade. Beyond that, the rubber wiper is subject toenvironmental factors such as temperature changes, UV radiation,seawater, exhaust gases etc., which may cause premature aging of thematerials and enhanced wear.

In principle, wear can be reduced by improved gliding properties,reduced friction and/or harder rubber wipers. German patent DE 26 23 216describes rubber wipers initially halogenated with chlorine or brominein a chemical wet hardening process and subsequently treated with amoderate to strongly alkaline solution at temperatures up to 100° C.

After producing the rubber wiper, for example by extrusion, it featuresa proper, smooth surface. The chemical wet hardening process affects therubber wiper in its entirety, so that its material properties change,even where that is not required or is very undesirable. Beyond that, itsmicrostructure and macrostructure are altered, for example by chlorineand heat. As a rule, the rubber turns coarser and more brittle,impairing its contact with the windshield and its wiping efficacy. Inaddition, there is a danger that small or larger particles may break outof the rubber wiper in wiping the windshield. Moreover, for propercleansing quality, the wiper lip should quickly and easily flip over inreversing its travel direction, without significant resistance. Yet,with harder and more brittle material, its resistance is increased,impeding or at least retarding the reversal process, and there is atendency for the wiper blade to rattle.

Belgian patent BE 84 8 964 A describes a coating process apt to improvethe gliding properties after a hardening process. Accordingly, therubber wiper receives at least in the area of the lip, by a chemical wetprocess, a coating which is softer than the base material and istherefore not particularly resistant to wear.

SUMMARY OF THE INVENTION

Coating processes wherein the coating materials are mixed or utilized ina vaporous state, then conveyed to the surface of the object to becoated, and deposited thereon may be basically classified as PVD(Physical Vapor Deposition) and CVD (Chemical Vapor Deposition)processes.

Such coating processes are especially known in coating silicon wafersfor integrated semiconductor circuits (cf. D. Widmann; H. Mader; H.Friedrich. 2nd ed. Springer 1996, p. 13-34). CVD processes, alsoreferred to as gas phase deposition processes, are triggered by chemicalreactions, in the sense that the applied coating materials turn into acoating in a chemical reaction on the coated surface. Conversely, PVDprocesses are primarily triggered by physical factors, such as forexample cathodic sputtering, although there is no clearcut dividing linebetween these processes.

The advantage of these processes consists in the possibility of creatingmany different, particularly thin, compact and highly cross-linkedcoatings. Thin layers, though hard, may be made flexible and resistantto break-up as the rubber wiper is deformed. The compact surface ispreserved, lending it high chemical resistance, in that no aggressiveagents, such as seawater, exhaust gases etc. will penetrate between thecoating and the rubber wiper to attack it and peel off the coating.

Beyond that, thin coatings require less coating materials. There islittle waste and the need to keep coating materials in stock is limited.Because of the limited quantity of materials, the coating equipment maybe readily sealed off tight towards the outside. There is no need forchemically aggressive solvents and the coatings require notime-consuming drying and hardening cycles. The production processes arefriendly to the environment, economical and well suited to large -scaleproduction.

Beyond that, a special advantage of these processes lies in the factthat while the wiper is being coated, the process parameters may besimply varied, and the properties of the coating may be altered within athin layer so as to match specific requirements. Within the innerstructure of the rubber wiper, it is possible to achieve in one singleprocess an elastic and soft coating system adapted to the properties ofthe rubber wiper, with a hard, wear-resistant outer coating.

In the transition from a soft to a thin and hard coating within analtogether thin coating system, the latter is on the whole elastic, withno more than limited effect on the elasticity of the rubber wiper, withwhich it is securely bonded. The coating system will not peel off whenthe rubber wiper is deformed, and it is chemically resistant.

Particularly advantageous is a smooth transition from elastic/soft tothe wear resistant/hard region. In one embodiment of the invention, itis proposed that the process parameters be varied, as for example theblending ratios of process gases, the electric or thermal input, thedistance between the source of the material and the rubber wiper, flowparameters, etc., so as to achieve an infinitely variable gradientlayer, that is, a layer whose stock parameters and properties followfrom inside out, perpendicular to the rubber wiper and consistent withthe chemical and morphologic gradients, possessing at all times constantproperties along one plane in the longitudinal direction of the rubberwiper. Nevertheless, under different boundary conditions in theproduction process, it may be more advantageous to alter processparameters gradually in order to produce a multi-ply layer, in otherwords, several overlapping thin layers deviating slightly in theproperties of the stock.

The gradient layer or multi-ply coating may at the same time form theouter hard and wear-resistant top coating. It is also possible to applythe wear-resistant hard coating in a separate deposition stage. Oneproposed embodiment of the invention envisages an additional finalapplication of a dry lubricant and/or hydrophobic coating. Good resultshave been achieved with coatings having a water wetting contact anglebetween 60 and 150 degrees, preferably over 90 degrees.

In one preferred embodiment, it is also possible to deposit only onehomogeneous gradient-free layer. This simplifies the deposition processand may lead to a distinct enhancement of wiper properties and wearresistance.

Particularly suitable as coating materials are halogen, silicon orcarbon-containing and/or metallo-organic materials or monomers, that is,low-molecular cross-linkable substances, whereby the carbon, nitrogen,oxygen, fluorine and/or metal content varies from the inside outward,enhancing hardness and/or wear resistance of the coating system. Forexample, an appropriate multi-ply layer or gradient coating may beattained with a silicon-based mixture, to which carbon is increasinglyadded during the process, that is, converted in a chemical gradient intoan increasingly carboniferous mixture. Particularly suitable for thefinal outer coating are carbon-rich compounds containing halogens and/ormetals, advantageously manufactured with fluorine-containing gases, lowoxygen siloxan monomers and hydrocarbon gases. The outer surface of thecoating is thereby endowed with the desired hydrophobic and/or drylubricant properties, with the resultant good gliding properties,especially on hydrophilic windshields. A higher coefficient of frictionmay result in an oxide or nitride multi-ply or gradient layer, whereby afinal hydrophobic coating apt to enhance the gliding properties isespecially advantageous. Such a final hydrophobic coating persists overan extended period of time by its co-valent bonding to the multi-plylayer or the gradient coating.

In order to enhance the stability of the overall coating system, oneembodiment of the invention proposes that the rubber wiper be cleansedand/or activated thermally, photochemically and/or in a plasma-assistedprocess, for example with halogen, oxygen and/or nitrogen-containinggases. The plasma fine-cleansing or activation and/or roughening of thesurface is preferably accomplished with microwave impulses and/orbiasing, or with a frequency generator operating at 13.56 MHz and aself-adjusting biasing potential. The bias is imparted by an electrodeover which the rubber wiper is guided with the rear side of the area tobe cleansed. The stability of the system may be further enhanced by ametallic, organic and/or silicon nitrogen containing adhesion-improvingcoating applied directly onto the rubber wiper. As a rule, such acoating is no more than a few 10's nm thick.

The coating materials may be compounded in a vaporous state by heat,plasma and/or laser means, and/or subjected to further breakdown whilealready in a vaporous state. True, heat-activated CVD processes have thedisadvantage that the rubber wiper is as a rule subjected to greaterthermal stresses, however, the heat may at the same time beadvantageously utilized as a pretreatment, leading to a denser filmgrowth.

One embodiment proposes that at least one of the processes beplasma-assisted. In relation to plasma-activated CVD processes, it ispossible to differentiate between a thermally activated hot plasma and afrequency activated cold plasma. Usable exciter frequencies range from50 KHz to 2.45 GHz, preferably 2.45 GHz with ECR magnetic fieldactivation, and most preferably 13.56 MHz. In the case of the thermallyactivated plasma, the heat may be used for the pretreatment oractivation of the rubber wiper, to achieve high rates of deposition andcost-effective coating systems. In order to secure intrinsically elasticcoating systems with the least possible stresses, the monomers arepreferably added in the colder ranges of the plasma, whereby themonomers are not fragmented into their atomic components, but formsofter and intrinsically elastic layers. Moreover, a faster film growthis achieved, with lower thermal stresses of the rubber wiper.

Where the plasma is generated by a frequency generator, for example ahigh-frequency, radio frequency or microwave frequency source, thethermal stresses on the rubber wiper may be minimized, as compared topurely CVD processes. With the input frequency, the radical portion, thedeposition rate and the film growth increase, reducing the processcosts.

The plasma generators may be operated continuously and/or pulsed. In thecase of the pulsed operation, the rubber wiper has a chance to recoverduring the intervals from the bombardment with the radicals, chargedparticles etc. and especially from thermal stresses. Cold gas moleculesare capable of dissipating the heat away from the rubber wiper. Beyondthat, it is possible to achieve a higher rate of film growth, in thatthe monomers are capable of preliminary reaction, thereby affording ahigher deposition rate.

For coating purposes, the rubber wiper may be passed directly through orover the plasma. When coated through the plasma, the thermal stress onthe rubber wiper is greater, however, with the fast growth of the film,it is possible to achieve hard, wear-resistant coatings within a shorterprocessing time. When coated outside the plasma, the rubber wiper isless stressed, the monomers may undergo preliminary reaction on the wayto rubber wipers, so that notwithstanding the losses occasioned by thegreater distance, it is possible to achieve high rates of deposition,fast growth of the film and softer coatings. It is also feasible to coatthe rubber wiper initially outside the plasma with a softer coatingadapted to the material of the rubber wiper, and then inside the plasma,with a harder, more wear resistant coating.

The plasma-assisted deposition of the layer may lead to denser, morewear-resistant coatings when the rubber wiper is exposed to a biasingpotential. As previously described in relation to the cleansing process,the rubber wiper is guided over an electrode carrying a biasingpotential. The bias is fed pulsed or unpulsed to ground or acounter-electrode. The pulse frequency lies between 10 KHz and severalMHz's, preferably 50 to 250 MHz. The biasing potential may also be fedfrom a frequency generator at 1 MHz to 100 MHz, preferably between 50MHz and 27 MHz, and most preferably 13.56 MHz. The biasing currentpropels ions from the plasma in the direction of the wiper surface,where they impact against the previously deposited layer leading to arenewed cross-linking/compacting of the coating. It is advantageous forthe biasing current to be self-adjusting at a level between a few voltsand 2 kilovolts.

One embodiment of the invention suggests using a laser-activatedprocess, notably a CVD process with one or several lasers. A laser, forexample an Excimer laser, is capable of inputting energy into aspatially circumscribed and exactly determinable area. In this way, thecoating system may be applied in a targeted, spatially limited area ofthe rubber wiper only, preferably in the region in contact with thewindshield. The rubber wiper is exposed to thermal stresses over a verylimited area only, leaving the elasticity of the rest of the wiperunaffected, particularly in the vicinity of the rocker flange, so thatthe reversing process is unaffected by the coating and the coatingsystem. The material and energy usage is lessened and the contaminationof the equipment is reduced. A further technical advantage lies in thefact that the laser coating process is always linear, since the energymay be concentrated onto a spot of limited diameter. Laminar coatingsare achieved by scanning the path of the laser beam. Rubber wiper edgesare linear substrates, which can in principle be coated without scanningthe beam, thereby saving optomechanical control elements, and adaptationto different substrates, simplifying synchronization of various beams,for example for pre-activation, the actual coating and renewedcross-linking.

All coating processes may be executed in such a way that the rubberwiper is coated on both sides, either simultaneously (for example, withtwo coating lasers) or in succession, on one side only, over the entiresurface, or just partially (for example, just the wiper lip, aspreviously described for the laser process).

Established purely PVD processes include plasma injection and sputter orcathode sputtering. Compared to vapor deposition processes in which thetreated articles are heated high enough to achieve vapor pressuresufficient for vaporization, cathode sputter permits better control ofthe coating composition, thereby achieving more uniform transitions.Beyond that, cathode sputter is a process capable of depositing atomsand atom compounds at lower temperatures, and hence affording bettercontrol of the temperature stresses on the substrate. In addition, inthe cathodic sputter as in other plasma-aided processes, the vaporcontains ions which may be drawn onto the layer and make it more compactwhen a biasing current is applied to the substrate; in the case of therubber wiper, that may involve a metal strip over which to guide thewiper lip.

Adapted to the contour of the rubber wiper is a hollow cathode injectorrepresenting a linear source to be preferably employed in cathodesputter. It is a source capable of elevated rates of deposition, coupledwith high-quality coatings. In addition, the hollow cathode possesses alarge linear spacing between the surface of the anode and the surface ofthe cathode, whereby in operating the injector a linear flow is attainedbetween the cathode and the anode, thereby preventing contamination andclogging of the cathode.

In the case of plasma injectors, a powder or liquid is fed to a plasmajet, fired by an electric arc, accelerated onto the rubber wiper anddeposited thereon fused or smelted.

The heat of the plasma may be at the same time used for the pretreatmentof the rubber wiper, thereby attaining particularly fast film growth.

In principle, the processes may be applied under vacuum or underatmospheric pressure. One embodiment of the invention proposes that theprocesses be performed under atmospheric conditions or at least underlimited vacuum, which do tend to produce more coarse-grained and softerlayers, dispensing with cost-intensive vacuum facilities and affordingas a rule higher rates of deposition.

For the coatings under atmospheric or low-vacuum conditions,particularly good results have been achieved with corona and/or barrierdischarge sources and/or plasma jets. With these techniques, it ispossible to achieve high rates of deposition and cost-effectivecoatings. Structurally, the coatings are soft and thereforeintrinsically well suited to matching the properties of the rubberwiper.

The PVD and CVD processes described here lend themselves to individualor combined use in different configurations. Where various differentprocesses are employed, it is advisable to use for the inner layerprocesses apt to produce fast film growth and soft layers matching thematerials of the rubber wiper. Best suited to the outer hard and thinregions are processes apt to produce with moderate film growth hard andwear-resistant layers. Preferably, the coating is incorporated in acontinuous production cycle, thereby saving space, time and cost.Particularly suited are continuous production cycles in which the rubberwiper is extruded and fed under atmospheric pressure throughdifferentially pumped vacuum or reaction chambers in contact with thecoating sources.

BRIEF DESCRIPTION OF THE DRAWING

Additional advantages are disclosed in the drawing described hereunder,illustrating exemplified embodiments of the invention. The drawing, thedescription and the claims contain numerous features in combination. Theexpert may give individual consideration to the characteristics, andconsolidate them into further rational combinations.

The drawings include:

FIG. 1 is a schematic cross-sectional view of the plasma source, in thisinstance a plasma jet source, and rubber wiper treated by it;

FIG. 2 is a diagrammatic view of several plasma sources arranged in arow and a rubber wiper coated by them;

FIG. 3 is a detailed cutaway cross-sectional view through a gradientprotective coating formed on a rubber wiper according to the invention;

FIG. 4 is a detailed cutaway cross-section view through a protectivecoating comprising several coating layers according to the invention;

FIG. 5. is a diagrammatic view of a coating installation incorporated ina rubber wiper production process.

DESCRIPTION OF EXEMPLIFIED EMBODIMENTS

FIG. 1 shows schematically a plasma source 20 with a ring-shaped anode32 and a rod-shaped cathode 34. On one side of the plasma source 20, aplasma gas 36 is fed past the cathode 34 and over the anode 32, beingthereby converted into a plasma-shaped state or activated into a hotplasma flow 30. A nozzle 38 lends the proper form to plasma 30. Toprevent combustion or fusing of the cathode 34, the anode 32 and thenozzle 38, the same are cooled through cooling water ducts 40, 42.

In the area of the anode 32, a monomer gas 44 is added to the plasma 30,fragmented by it and propelled in the direction of a rubber wiper 10.The rubber wiper 10 is fed at a distance 46 along the plasma 30 in thedirection 52, so as to give the fragmented monomer gas 90 on the way tothe rubber wiper 10 sufficient time for a preliminary reaction.Nevertheless, it is also possible to feed the rubber wiper 10 throughthe plasma 30, to be coated in the process. The monomer gas 90 depositsonto the rubber wiper 10 and reacts on its surface 48 into a highlycross-linked coating system 50 or an individual coating. It is alsopossible to feed in lieu of the monomer gas 44 a pulverized coatingmaterial to the plasma 30, to be fused by it, propelled in the directionof the rubber wiper 10 and form on its surface 48, with or without achemical reaction, a coating system or an individual coating.

FIG. 2 shows several plasma sources 22, 24, 26, 28 arranged in sequence,along which the rubber wiper 10 is fed in direction 52. In order toachieve within the coating system 50 in direction 54 perpendicular tothe rubber wiper 10 different substance properties, the plasma sources22, 24, 26, 28 are operated with gases of different composition orconcentration. It is furthermore possible for the plasma sources to beoperated at different performance levels or arranged at differentspacings away from the rubber wiper 10.

With the different plasma sources 22, 24, 26, 28, it is possible toproduce a sequence of many thin, different coatings, also designated asmulti-ply layers 14, and/or a gradient layer 12, wherein the parametersand the properties of the materials change consistent with one orseveral infinitely variable chemical gradients (FIGS. 3 and 4). Thegradient layer 12 is obtained by a suitably short array of plasmasources 22, 24, 26, 28 or by feeding the rubber wiper 10 past the plasmasources 22, 24, 26, 28 at a commensurate speed. In the process, thecoating materials blend on the surface 48 of the rubber wiper 10.Moreover, the fragmented monomer gases 90, even before impacting therubber wiper 10, may be mixed by the resultant flows 56 or by thecorresponding angles of emission of the plasma sources 22, 24, 26, 28.It is also feasible for the rubber wiper 10 to be guided step by stepalong the length 58 of the coating range 60, and operate the plasmasources 22, 24, 26, 28 uniformly, while changing the composition of thegas and/or the energy input over a period of time, in order to produce agradient layer 12 or a multi-ply layer 14. Nevertheless, a continuouscoating process can be more favorably incorporated in the productioncycle of a rubber wiper 10.

In order to ensure superior adhesion of the coating system 50, 62, anadhesion-enhancing layer 18 is applied in a first step onto the rubberwiper 10, as illustrated in the magnified cutouts of rubber wiper 10shown in FIGS. 3 and 4. Next, the gradient layer 12 shown in the exampleof FIG. 3, and the multi-ply layer 14 shown in the example of FIG. 4were applied. The coating systems 50, 62 both terminate with a hard,thin and wear-resistant layer 16. It is also possible for the rubberwiper 10 to be coated with just one gradient layer 12 or just onemulti-ply layer 14.

Both of these coating systems 50 and 62 are internally elastic and soft,matched to the material properties of the mostly elastomer-constructedrubber wiper 10. In direction 54 perpendicular to the rubber wiper 10,the hardness increases up to the outermost layer 16, thereby creating awear-resistant, inherently flexible coating system 50, 62, able to matchthe deformations of rubber wiper 10 and remain safely bonded theretoover an extended period of time. Along with the continuous increase ofhardness within the coating systems 50, 62, it may prove advisable toalternate between hard and soft layer surfaces, for examplesoft/hard/soft/hard, in order to enhance the elasticity of the systemand/or reduce stresses. The coating systems 50, 62 are preferablybetween 200 nm and 2 μm thick.

FIG. 5 illustrates a vacuum-operated coating plant 64, incorporated inthe production cycle of a rubber wiper 10. In the first stage, theelastomer is extruded in an apparatus 66 into a strand-shaped rubberwiper 10. Next, the rubber wiper 10 is fed to the coating apparatus 64,featuring in its mid-section a coating chamber 68 with coating jets 70connected to high vacuum pumps 72, 74.

The high vacuum pumps 72, 74 are destroyed if operated againstatmospheric pressure. To prevent this, preliminary vacuum chambers 80,82, 84, 86 connected to rough vacuum pumps 76, 78 are provided in thefront and rear regions of the coating apparatus 64. The vacuum pumps 72,74, 76, 78, and especially the high vacuum pumps 72, 74 are preferablymounted in the upper portion of the coating apparatus 64, so thatpossible larger particles dropping downwards from the coating materialdo not enter and damage the vacuum pumps 72, 74, 76, 78. The plasma jets22,24,26,28 may be mounted above the substrate bushing, or on the sidesof the coating chamber 68, to coat the substrate simultaneously on bothsides, or successively first on one side and then the other. Followingthe coating apparatus 64, the rubber wiper 10 is separated into therequired lengths in an apparatus 88. This may also be done before thecoating apparatus 64 in a different suitable installation.

What is claimed is:
 1. A process for coating a rubber wiper made of anelastomer material with a protective coating, said process comprisingthe steps of: a) generating and activating a vaporous coating material(90) by means of at least one of a plasma and a laser; b) forming theprotective coating (50,62) on a surface (48) of the rubber wiper (10) byexposing said surface (48) to the vaporous coating material (90) by atleast one of a chemical vapor deposition method and a physical vapordeposition method; and c) controlling process parameters for thegenerating and activating of the vaporous coating material and for theforming of the protective coating on the surface of the rubber wiper(10) so that said protective coating (50,62) includes at least threecoating layers, said protective coating has a total thickness of from200 nm to 2 μm, said at least three coating layers include at least onethicker softer one of said coating layers having elastomeric propertiescorresponding to those of said elastomer material and other thinnerharder ones of said coating layers, and the other thinner harder coatinglayers have respective hardness increasing from an inner most one to anoutermost one of said other thinner harder coating layers.
 2. Theprocess as defined in claim 1, wherein said other thinner harder coatinglayers alternate with respective ones of said at least one thickersofter coating layer.
 3. The process as defined in claim 1, wherein saidprotective coating on said surface of said rubber wiper has acontinuously increasing hardness from said surface of said rubber wiperto an outer surface of said protective coating.
 4. The process asdefined in claim 3, wherein during the controlling said processparameters are continuously varied.
 5. The process as defined in claim1, wherein during the controlling said process parameters are changed ina step-wise manner and said protective coating (50) comprises amulti-ply layer (14).
 6. The process as defined in claim 1, furthercomprising forming a final topmost layer of said protective coating andwherein said final topmost layer of said protective coating consists ofa hydrophobic and lubricating layer (16) having a water-wetting anglebetween 90 and 150°.
 7. The process as defined in claim 1, furthercomprising applying a bias voltage to said rubber wiper (10) during theforming of the protective coating by means of an electrode andpre-treating said rubber wiper (10) with said plasma produced with amicrowave discharge at 13.56 MHz.
 8. The process as defined in claim 1,further comprising applying a 10 nm thick adhesion-enhancing layer (18)to said rubber wiper (10) as an initial step in the forming of theprotective coating on the rubber wiper (10) and wherein saidadhesion-enhancing layer (18) comprises at least one member selectedfrom the group consisting of metallic materials, organic materials andsilicon-containing materials.
 9. The process as defined in claim 1,further comprising producing said plasma (3) with a plasma excitationsource having a frequency between 50 KHz and 2.45 GHz and supplying amonomer gas (44) or a powdery coating material to said plasma (30) inthe vicinity of an anode (32), and wherein the generating and activatingof said vaporous coating material (90) from the monomer gas (44) or thepowdery coating material takes place by means of said plasma (30). 10.The process as defined in claim 9, wherein said plasma excitation sourceis operated with magnetic field activation and said frequency is 2.45GHz.
 11. The process as defined in claim 9, wherein said frequency is13.56 MHz.
 12. The process as defined in claim 9, wherein said plasmaexcitation source comprises a plurality of pulsed sources (20, 22, 24,26, 28).
 13. The process as defined in claim 1, further comprisingcoating the rubber wiper with one comparatively softer layer outside ofsaid plasma and then with another comparatively harder layer in saidplasma.
 14. The process as defined in claim 1, wherein said activatingof said vaporous coating material (90) takes place by means of saidlaser and said forming of said protective coating on said surface onlytakes place on a portion of said surface which comes into contact with awindshield on which said rubber wiper is installed.
 15. The process asdefined in claim 1, wherein said generating and said activating of saidvaporous coating material (90) for the forming of the protective coatingtakes place by means of said plasma and wherein said plasma is producedby a hollow cathode source, a corona discharge source or a barrierdischarge source at or below atmospheric pressure.
 16. The process asdefined in claim 1, further comprising applying a biasing potential tosaid rubber wiper by means of an electrode mounted behind said rubberwiper, whereby ions from said plasma are attracted to said rubber wiperduring the forming of the protective coating.
 17. The process as definedin claim 16, wherein the biasing potential applied to said rubber wiperis a pulsed potential having a pulsing frequency from 10 KHz to two MHz.18. The process as defined in claim 17, wherein said pulsing frequencyis from 50 to 250 KHz.
 19. The process as defined in claim 1, consistingof a continuous production cycle performed with differentially pumpedcontinuous processing equipment and wherein said differentially pumpedcontinuous processing equipment includes a vacuum-operated coating plant(64), said vacuum-operated coating plant (64) includes preliminaryvacuum chambers (80,82,84,86) and rough vacuum pumps (76,78) connectedto said vacuum chambers in a front and rear region thereof as well ashigh vacuum pumps (72,74) in an upper region thereof.
 20. The process asdefined in claim 19, further comprising arranging respective plasmasources (22, 24, 26, 28) in succession one after the other in saidvacuum-operated coating plant (64), moving said rubber wiper (10) in adirection (52) by said plasma sources and operating said plasma sourceswith at least one of correspondingly different gas compositions andcorrespondingly different gas concentrations.